Irrational Games finished the first "BioShock" in 2007. Since then, we haven't heard a peep from the Boston-based developer. After passing "BioShock 2" on to 2K Marin, many thought the "BioShock" brand had left Irrational and its creator, Ken Levine. Turns out, many were wrong. Irrational has been working on the next installment in the franchise, "BioShock Infinite," since 2008, and it's definitely not just another return to Rapture.

Welcome to Columbia

"BioShock Infinite" is set in the city of Columbia. It's a massive city in the sky, floating on hot air balloons and propellers. In the twisted timeline of "Infinite," Columbia was created by the US government in 1900 and revealed to the world at large (unlike the secret city of Rapture). Columbia was designed as a way to show the world the technological strength of America. Ken Levine describes it as the equivalent of the "moon landing of 1900." Basically the city would float around the world and show all the other countries how lacking they were compared to America.

Shortly after the time that it was launched, there was an international incident of some sort. Irrational isn't saying exactly what happened, but something went wrong and it was revealed that Columbia wasn't just a technological marvel, it was also a devastating weapon. Levine goes so far as to call it "a Death Star."

And then Columbia vanished.

Enter Our Hero, Booker DeWitt

It's been 10 years since Columbia disappeared in the clouds. Booker DeWitt is a former Pinkerton agent living in New York City who now acts as a fixer...someone who gets things done. He's no saint, but if there's enough cash on the table, he's your man.

One day Booker is approached by a mysterious man who needs him to find a girl named Elizabeth. Where is she? Columbia, of course. Thus Booker is somehow brought to the floating city of Columbia to find this girl and unravel the mystery of what occurred there.